1. Field of the Invention
This invention relates to automotive vehicles having suspension systems that include gas levelers for adjusting vehicle ride height, and in particular it relates to detecting when such a vehicle is being either hoisted or jacked.
2. Background Information
In certain situations involving a vehicle of the type to which this invention relates, it may be desirable for the vehicle to have a self-diagnostic capability that enables it to automatically detect when it is being hoisted or jacked. Hoisting is customarily considered raising, from above by a device such as a hoist, a portion of a vehicle to relieve some or all of a portion of the vehicle weight applied at one wheel, or at a set of wheels such as the front wheels or the rear wheels. At an extreme, the weight is fully relieved by lifting the wheel, or set of wheels, off an underlying support surface. Jacking is customarily considered raising, from below by means of a device such as a jack, a portion of a vehicle to relieve some or all of a portion of the vehicle weight applied at one wheel, or at a set of wheels such as the front wheels or the rear wheels. At an extreme, the weight is fully relieved by lifting the wheel, or set of wheels, off an underlying support surface.
The suspension system of a vehicle of the type to which the present invention relates includes gas levelers that under certain conditions operate automatically to maintain predetermined vehicle ride heights at the wheels so that the vehicle remains generally level and insensitive to changes in load and/or load distribution within its load carrying capacity. When the vehicle weight applied at one or more wheels is relieved by apparent hoisting or jacking, it may be desirable for the automatic operation of the gas levelers to be interrupted, or inhibited. If a vehicle is equipped with a self-diagnostic capability that automatically detects apparent hoisting or jacking, it can automatically inhibit any vehicle leveling that might otherwise occur if the vehicle were not being apparently hoisted or jacked.
A preliminary novelty search in connection with this invention developed the following U.S. Pat. Nos. 4,709,934; 4,783,089; 4,965,878; 5,083,454; 5,286,059; 5,652,703; and 5,696,678.